This invention, in terms of apparatus, relates to an anchor for being releasably attached to an automobile to provide an anchor point or pulling point when straightening the frame or body of the automobile. In terms of method, the invention includes using the hook to straighten automobile bodies of unitized construction.
In the past, conventional body construction of American made automobiles generally has included a frame having a pair of spaced apart, longitudinally extending, parallel frame members, or rails, supporting opposite underside portions of the automobile body. Such frame members are part of a rigid framework which includes cross-members extending between the rails. The body of the automobile is rigidly affixed to this framework.
When repairing frame damage on such automobiles, a power-pull system typically is used in which one end of the automobile frame is anchored by a chain or cable extending from the frame to a tie-down point on the ground, and a pulling force is applied to the opposite end of the frame from a chain or cable engaged with a hydraulic pulley apparatus. It is a relatively simple matter to find secure points for attaching the ends of the chains or cables to the front and rear portions of the frame members when straightening the frame.
In recent years the energy shortage and resulting higher gasoline prices have resulted in greater use of compact automobiles in this country. A large number of these vehicles have bodies of so-called unitized construction in which the body is generally of integral construction and is not attached to a separate body-supporting framework such as that described above. The main structural portions of the unitized body include so-called sill panels, or rocker panels, which are hollow metal beams extending along opposite sides of the automobile body below the door panels.
When straightening a body of unitized construction, the present procedure is to attach a unitized body clamp to an anchor point or pulling point on the bottom side of the rocker panel. This area of the rocker panel has a pair of side-by-side elongated flanges which extend away from the underside of the rocker panels and are pinch-welded together along the length of the rocker panels. The unitized body clamp has opposite faces which are bolted together into contact with the opposite sides of the flanges below the rocker panel. The clamps have teeth which bite into the metal flanges when the clamps are bolted to provide a good grip for an anchor point or pulling point. In recent years the metal used in many unitized bodies, including the rocker panels, has no been strong enough to withstand tearing or other marring of the appearance of the automobile body when a pulling force of sufficient magnitude to straighten the body is applied via unitized body clamps attached to the flanged portions of the rocker panels.